Two Paramecia: (1) Aborted Phagocytosis, (2) Extended Radial Canals

About the shape and function of different specimens
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linuxusr
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Two Paramecia: (1) Aborted Phagocytosis, (2) Extended Radial Canals

#1 Post by linuxusr » Sat Oct 23, 2021 2:36 pm

Here are two Paramecia (and a bubble!):

In the upper left you see an aborted phagocytosis. In the lower right you see unusually long and extended radial canals emanating from the Contractile Vacuole (CV):

https://youtu.be/hCwAp2Qio3E


It is interesting that the phagocytosis abort is instantaneous, as if it is triggered by a stimulus. These kinds of behaviors are referred to as taxes (plural). A
taxis
(singular) is named after the stimulant, so in thermotaxis the stimulant is heat. If the organism withdraws from the stimulant that is a negative taxis and if it proceeds to it that is a positive taxis.

This specimen demonstrates a negative taxis, stimulus unknown. My guess is that in microscopy there is a high probability of negative thermotaxis due to radiation from the LED/halogen lamps.

In the link following you can download a free .pdf from The Biology of Paramecium , Second Edition, Ralph Wichterman, 1986. From the Table of Contents you can find a series of taxes in Ch. 6, B. You will also find a bibliography. The ebook costs $149 USD and I must say I am very tempted:

https://link.springer.com/content/pdf ... F1.pdf

Can anyone identify the food source? I am thinking that it is an aggregate of chloroplasts rather than algae?? For that matter, it may be an endosymbiont unrelated to food. The foregoing are unknowns to me requiring more study.

There are several themes indicated here that could be explored in other posts:
a. Types of ingestion: bacteria via the cytostome (“mouth”) versus endosymbionts in the endoplasm versus food sources degraded in the food vacuoles,
b. Energy production: When you see the several thousand rapidly beating cilia as well as the constant action of the two CV’s you are impressed by how much energy the organism requires! Much of this energy in the form of ATP is produced by glycolysis in the mitochondria of the nucleus. But what are the linkages between ATP in the nucleus and the food as an energy source in the vacuoles?

Paramecium sample 2, lower right:

On the dorsal side of the specimen, you find two Contractile Vacuoles that osmoregulate the organism. If the solutes within the cell wall become too hypertonic, the organism could lyse (burst). The CV’s vacate excess solutes at regular intervals.

Radiating from the CV’s are the radial canals. When I first saw these I thought they were openings in the cell wall. Now I realize that they are structures, discrete bodies, three-dimensional, that channel solutes to the CV’s.

What makes this video unusual is that the radical canals appear much longer and extended than usual. I suspect that these locations are constants in the organism but that I just happened to chance on an angle whereby one can observe more of the structure that is normally hidden by the thousands of dynamic particles making up the endoplasm.

When I investigated a little further, I was shocked to find an unexpected detail: Paraphrasing from the following, a very nice synopsis of Paramecium morphology, it turns out that the radial canals extend all the way to the ER (Endoplamic Reticulum) in the nucleus! This is most surprising!

The linkages are: water < cytoplasm < ER < nephridial tubules < feeder canals < storage in ampullae < CV < pellicle pore < external environment:



http://www.jesjalna.org/zoology/pdf/ ... 0..pdf
Nikon AlphaPhot 2 < Zeiss Primostar 3, Full Köhler; Axiocam 208 Color < UHD LG
Aller Anfang ist schwer.

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